4wd not working

I had a similar problem with my rear diff lock. Check out this thread- https://www.tacomaworld.com/threads/e-locker-actuator-troubleshooting.613739/

I had the same result as described in post #9- a bad ground that was fixed by doing the grey wire mod. Happy camper now with a working rear diff lock.

 

Hey I want to slip in here as long as y’all promise not to laugh. I’ve got an 03 4wd and I didn’t know there was a button. I thought you just put it in neutral and shifted to 4wd. Is this not right?

 

There's a button for the 2-4 push button transfer case and no button on the j-shift transfer case.